Leak Test of the Accessory Gearbox pad (AGB) Starter cavity (between equipment and AGB) [CFMB]

TASK 71-00-00-790-008-A
Leak Test of the Accessory Gearbox pad (AGB) Starter cavity (between equipment and AGB)

WARNING: BE CAREFUL WHEN YOU DO WORK ON THE ENGINE PARTS AFTER THE ENGINE SHUTDOWN. USE APPLICABLE THERMAL GLOVES. THE ENGINE PARTS CAN STAY HOT FOR ONE HOUR AFTER SHUTDOWN AND CAN BURN YOU.

1. Reason for the Job
To make sure that there is no starter drive shaft missing or damaged o-ring causing oil leakage.
This procedure can be applied to all AGB pads receiving hydraulic equipement on all CFM engine model.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	AR	WARNING NOTICE(S)
No specific	Torque wrench: range to between 250 and 200 lbf.in (2.83 and 2.26 m.daN )
No specific	Torque wrench: range to between 255 and 200 lbf.in (2.88 and 2.26 m.daN )
856A2675G01	1	LEAK TEST TOOL SET

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
FOR [1000EM1] (ENGINE-1)
437AL, 438AR
FOR [1000EM2] (ENGINE-2)
447AL, 448AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 71-13-00-010-040-B	Opening of the Fan Cowl Doors
TASK 71-13-00-410-040-B	Closing of the Fan Cowl Doors
TASK 71-73-49-000-003-B	Removal of the Starter Pad Oil Drain Tube
TASK 71-73-49-400-003-B	Installation of the Starter Pad Oil Drain Tube
AGB Starter Pad Drain Sealing Check

3. Job Set-up
Subtask 71-00-00-941-079-A ** ON A/C NOT FOR ALL

A. Safety Precautions
(1) On the center pedestal, on the ENG panel 115VU:
(a) Put a WARNING NOTICE(S) to tell persons not to start the engine.
(2) Make sure that the engine 1(2) shutdown occurred not less than 5 minutes before you do this procedure.
(3) On the overhead maintenance panel 50VU:
(a) Make sure that the ON legend of the ENG/FADEC GND PWR/1(2) pushbutton switch is off.
(b) Put a WARNING NOTICE(S) to tell persons not to energize the FADEC 1(2).

Subtask 71-00-00-010-109-A ** ON A/C NOT FOR ALL

B. Open the fan cowls: (Ref. AMM TASK 71-13-00-010-040)
(1) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(2) FOR [1000EM2] (ENGINE-2)
447AL 448AR

4. Procedure
Subtask 71-00-00-010-110-A ** ON A/C NOT FOR ALL

A. Remove the starter pad oil drain tube (Ref. AMM TASK 71-73-49-000-003).

Subtask 71-00-00-480-063-A ** ON A/C NOT FOR ALL

B. Sealing tool installation.

AGB Starter Pad Drain Sealing Check ** ON A/C NOT FOR ALL

(1) Remove the storage plugs from tool 856A2675G01 LEAK TEST TOOL SET.
(2) Take sealing tool and connect flexible hose of the tool to AGB drain nipple and TORQUE to between 250 and 200 lbf.in (2.83 and 2.26 m.daN )

.
(3) Connect flexible hose to air or nitrogen supply and TORQUE to between 255 and 200 lbf.in (2.88 and 2.26 m.daN )

Subtask 71-00-00-720-055-A ** ON A/C NOT FOR ALL

C. Test process.

CAUTION: DO NOT OVERPRESSURIZE THE CAVITY. IF YOU PRESSURIZE IT TO MORE THAN 199.95 KPA (29 PSI), MAG SEAL SEPARATION CAN OCCUR.

(1) Open air or nitrogen air supply source and pressurize cavity to 7.25 Psi (0.5B).
(2) Close isolation valve to isolate AGB cavity.
(3) Check sealing cavity, there must be no pressure decrease during 1 minute test.
A quick pressure decrease indicate a damaged o-ring, difficulties to isolate cavity and maintain pressure, indicate a missing o-ring on starter output shaft. Both cases involve starter removal and o-ring replacement or installation.
(4) After seal replacement, perform leak check again to verify cavity sealing.
(5) After test completion, remove sealing tool and reinstall starter pad oil drain tube.

Subtask 71-00-00-410-106-A ** ON A/C NOT FOR ALL

D. Install the starter pad oil drain tube (Ref. AMM TASK 71-73-49-400-003).

5. Close-up
Subtask 71-00-00-410-107-A ** ON A/C NOT FOR ALL

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the fan cowl doors (Ref. AMM TASK 71-13-00-410-040):
(3) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(4) FOR [1000EM2] (ENGINE-2)
447AL 448AR
(5) Remove the WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 13:14:05 UTC